Fix potentially broken nginx_upstream.
Fix potentially broken nginx_upstream.

This fixes #2028.

Accepts php or any valid upstream in the /etc/nginx/upstreams directory.

Example output https://prnt.sc/qc4r2y.
Varying-Vagrant-Vagrants/VVV,saucal/VVV,speartail/VVV,trepmal/varying-vagrant-vagrants,speartail/VVV,saucal/VVV,Varying-Vagrant-Vagrants/VVV,saucal/VVV,Varying-Vagrant-Vagrants/VVV,trepmal/varying-vagrant-vagrants